A completely automated public Turing test to tell computers and humans apart (“CAPTCHA”) is a type of challenge-response test that may be used to determine whether a device (e.g., a computer device) is being operated by a user (e.g., a human) or by the computing device (e.g., an automated process being performed by the computing device). A CAPTCHA may require the user to correctly transcribe a group of distorted characters (e.g., letters) included in a CAPTCHA image (e.g., the computing device may be unable to identify the distorted characters).